The Population Research and Effectiveness (PRE) Core replaces and augments the prior Research Design and Analysis Core and will contribute to the goals of the Mount Sinai OAIC by providing statistical, methodological and programming expertise, as well as mentoring in those areas, to OAIC investigators. This core has been highly productive in providing consultations and support for numerous OAIC investigators confronted with methodological and analytic issues that occur in the study of older adults with serious illness. For this application, we have assembled a cadre of experts, some who have served as past consultants and some who are new, with a broad range of knowledge regarding research methods to serve as potential consultants to OAIC investigators and projects. Resources and expertise will be provided in a variety of ways and throughout all phases of the research process - from design to interpretation and presentation of findings. In addition to this research support, the RC-PRE will support a sequence of pilot projects leading to the formation of a large, population-based dataset (Developmental Project (DP) 1) of seriously ill patients that is innovative in its scope and inclusion of information on demographics, healthcare use, chronic conditions, symptoms, and function to be used for multiple areas of research related to the objectives of the OAIC. A second developmental project will advance current methodologies for analyzing observational data. The specific aims of the RC-PRE are: 1) To provide sophisticated, cutting edge methodological, statistical, and programming support to OAIC investigators; 2) To apply advanced research and statistical methodology (e.g., propensity scores, instrumental variable estimation, competing risk analysis) used in other fields but not commonly applied to aging-related research; 3) To collaborate closely with the RCDC and RCDSC to ensure that junior faculty obtain research methods training to advance their current knowledge and expertise; 4) To create and manage a large, population-based dataset to be used by OAIC investigators for research regarding individuals with serious illness (DP-1) and advance the methods to analyze these data (DP-2); 5) To maintain an inventory of large population-based datasets housed at Mount Sinai with the goal of identifying outcome measures for new studies of patients with serious illness. Through consultations with experts on a range of topics addressing the methodological, logistical and statistical issues encountered in the study of seriously ill older adults and the development of research infrastructure, this Core aims to advance the rigor of geriatric palliative care research and support future geriatric palliative care research endeavors.